FIG. 1 shows an example of part of an interconnected network 100 of computers 102 and servers 104, using the internet protocol suite, and that together form a small portion of the internet. One or more of the servers 104 may host digital content, such as web pages, accessible by users of the computers 102. One or more of the servers may also act as an internet service provider for groups of the computers 102. The computers 102 could include laptops, PC's (personal computers), mobile telephones with internet access, and other mobile devices able to access the internet.
In recent years there has been a growth in the use of websites that allow users to voice opinions on public forums hosted on the internet. For example, websites such as Twitter and Facebook (the names “Twitter” and “Facebook” are likely to be registered trademarks) allow users to make comments and add links to articles, expressing positive or negative opinions on a wide range of subjects. Such comments and opinions may be relayed very quickly through the internet, propagated by users through the servers 104 and computers 102 of the network 100, often in just a matter of hours.
It would be advantageous to be able to monitor the rapid growth of internet activity regarding a given subject. However, there is a technical problem in tracking this type of activity over the internet.